Democratic Kampuchea was the official name of Cambodia/Kampuchea from 1976 to January 1979, during the Khmer Rouge Years, though the international community recognized it for ten more years. Its leader was Pol Pot, and its national anthem (song) was Dap Prampi Mesa Chokchey. It was succeeded by the People's Republic of Kampuchea upon the Vietnamese invasion in 1979. While Democratic Kampuchea existed, about 20% of its population died either because of starvation, brutality, or execution. The four-year period saw the deaths of approximately two million Cambodians through the combined result of political executions, starvation, and forced labour. Due to the large numbers, the deaths during the rule of the Khmer Rouge are often considered a genocide, and commonly known as the Cambodian Holocaust or Cambodian Genocide. The Khmer Rouge period ended with the invasion of Cambodia by neighbour and former ally Vietnam in the Cambodian–Vietnamese War, which left Cambodia under Vietnamese occupation for a decade.